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Ibbo

Trying to get the pup

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Ibbo

Last 2 nights I have tried and failed to get the pup visually.

Try one - C11 and 16 & 7mm eyepeice (skywatcher Nirvana and a 20mm type 2 nagler for the moon and M42 and other bits and bobs))

Try 2 - 8" Meade SCT with same eyepeices.

 

To start with lets say I am well out of practice with the mark1 eyeball.

 

Both scopes had been sat out on the mount for a minimum of 3 hours (more like 4).

I had a tweak of the collimation on both.

I have positioned the mount so when it trnsits I have a gap in the houses 300 meters away and avoid my garage roof.

Now to the problem I know Sirius is seriously bright and low down from here about 20° max above the proper horizon, I am getting a flare of sirius - blue through yellow to red.

Is this down to the seeing ,altiude collimation, eyepeices or the diagonal or anything else anybody can think of.

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philjay

Never seen it myself but spoken to many who have, seeing has a lot to do with it apparently. A big refractor would help also :-)

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Doc

I think I saw it once in my big dob but I cannot find the report of it. Should be visible in a good refractor, but from what I've read seeing is really important and a mag of about x250.

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Bino-viewer

I've never seen it, and tried plenty of times.

Antares is another case of wishful thinking.

 

I always have a look at the 'trap' in M42 first.

If theres a sniff of the 'E' star (rare) i will then try for Sirius B.

 

One day........:lol: i may get lucky !!

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Tweedledee

I'm sure I read somewhere that a Baader Contrast Booster filter or similar can help.

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philjay

I reckon a polarising filter may help, I find they work will with doubles especially with bright primaries

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Graham

This has me intrigued.

What are you lot on about.

What is this 'PUP' ???

Thanks

 

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Orion
On 12/29/2017 at 22:08, Bino-viewer said:

I've never seen it, and tried plenty of times.

Antares is another case of wishful thinking.

 

I always have a look at the 'trap' in M42 first.

If theres a sniff of the 'E' star (rare) i will then try for Sirius B.

 

One day........:lol: i may get lucky !!

Can you try an occulting bar?

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Orion
On 12/29/2017 at 16:42, Ibbo said:

Last 2 nights I have tried and failed to get the pup visually.

Try one - C11 and 16 & 7mm eyepeice (skywatcher Nirvana and a 20mm type 2 nagler for the moon and M42 and other bits and bobs))

Try 2 - 8" Meade SCT with same eyepeices.

 

To start with lets say I am well out of practice with the mark1 eyeball.

 

Both scopes had been sat out on the mount for a minimum of 3 hours (more like 4).

I had a tweak of the collimation on both.

I have positioned the mount so when it trnsits I have a gap in the houses 300 meters away and avoid my garage roof.

Now to the problem I know Sirius is seriously bright and low down from here about 20° max above the proper horizon, I am getting a flare of sirius - blue through yellow to red.

Is this down to the seeing ,altiude collimation, eyepeices or the diagonal or anything else anybody can think of.

I would guess that the red blue flicker, is mostly due to refraction through the low altitude.  I've read that some people have seen the companion star by using an occult bar, and to position it, or look for it, at a time when the star doesn't get blotted out by the bar. So the position angle is important to know in relation to the position of the occult bar when observation takes place.  I'm not sure where the bar is placed (eyepiece or objective).  Didn't you try a bar across the objective?  A piece of wire would probably suffice.

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Tweedledee

A bar across the objective would not do the trick. It needs to be at the field stop of the eyepiece. They used to be used many years ago but I've never seen a commercially available occulting bar eyepiece. Apparently they can be made. 

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Orion

Yes, I'm sure that a thin piece of wire placed across the stop would be a good idea. It could be trial and error getting the right material and diameter sufficient to block out enough light from Sirius.  Ordinary cross hair wire?  An example of a thin wire is wire from a filament in a electric light bulb, or the molybdenum wire that supports the filament.  I've never tried it yet.

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Tweedledee
5 minutes ago, Orion said:

Yes, I'm sure that a thin piece of wire placed across the stop would be a good idea. It could be trial and error getting the right material and diameter sufficient to block out enough light from Sirius.  Ordinary cross hair wire?  An example of a thin wire is wire from a filament in a electric light bulb, or the molybdenum wire that supports the filament.  I've never tried it yet.

I think that a thin wire would be fine, but it could be much easier to use a wider bar, or even just cut off one half of the field of view completely at the the focal plane/field stop position. I think it would work fine provided the edge of the occulting bar is a precise knife edge which can be focused sharply and not in any way fuzzy.

 

Here's a .pdf showing how to make one very simply...

http://www.eagleseye.me.uk/Resources/OccultingBar.pdf

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Orion

Thanks, downloaded for future project.

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Tweedledee

Besides lots of double stars, there are a few nebulae/galaxies near to bright stars that can benefit from using an occulting bar. The ones that spring to mind are galaxy NGC 404 near Mirach (the Ghost of Mirach) and the gamma Cassiopiea nebula. Some of these can be seen better by simply keeping the star outside the field of view, but an occulting bar can sometimes be better to keep the faint object closer to the centre and sharpest part of the eyepiece field of view. Also faint moons like Phobos and Deimos can be better seen by occulting Mars with a bar.

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